涡旋压缩机的径向迷宫密封研究

Research on the Radial Labyrinth of Scroll Compressor

针对涡旋压缩机径向密封难以实现的难题,提出一种径向迷宫密封。用几何学和热力学方法证明基圆渐开线型涡旋压缩机径向光滑间隙密封中的泄漏气速达到声速,分析径向光滑间隙密封中泄漏气体的热力变化过程,根据临界截面上气体的气动热力特性,推导出考虑边界层摩擦损失的径向光滑间隙密封泄漏量的算法,根据能量方程和连续性方程,推导出判定径向迷宫密封中泄漏气速是否达到声速的判别式和径向迷宫密封泄漏量的算法。计算和实测两种密封在一系列相邻压缩腔压差对应下的泄漏量。理论计算和试验对比表明,给出的两种密封泄漏量的算法正确;径向光滑间隙密封和径向迷宫密封的泄漏量均随着相邻压缩腔压差的增大而增大;径向迷宫密封的直通效应随着相邻压缩腔压差的增大而更加明显;径向迷宫密封泄漏量实测值约为径向光滑间隙密封泄漏量实测值的79%,说明径向迷宫密封的密封性能优于径向光滑间隙密封的密封性能。

A kind of radial labyrinth for scroll compressor’s radial sealing is presented.By using geometric and thermodynamic method,the velocity of gas in radial sealing with smooth clearance of circumferential involute scroll compressor is determined as speed of sound,thermodynamic vary of gas in radial sealing with smooth clearance is analyzed,on the basis of the thermodynamic and boundary particularities,the algorithm to calculate the leakage through radial sealing with smooth clearance is developed,according to the law of the conservation of energy and mass,discriminant for judging whether the velocity of gas in radial labyrinth comes up to speed of sound is deduced,and the algorithm to calculate the leakage through radial labyrinth is also deduced.The leakage under the different pressure differences of the two adjoining pressure chambers are obtained by calculation and experiment.The results show that the algorithms for the leakages of the two kinds of structures are correct,with the increase of the pressure differences of the two adjoining pressure chambers,the leakages of the two kinds of structures become large,and the straightforward leak effect of radial labyrinth become clear,the ratio of the experimental leakage of the radial labyrinth accounts for that of the radial sealing with smooth clearance is practically constant at about 79%,it shows that the radial labyrinth has better sealing performance compared with the radial sealing with smooth clearance.